OAKLAND, Calif.— The Center for Biological Diversity and the Center for Environmental Health filed a formal notice of intent today to sue the U.S. Environmental Protection Agency for failing to address harmful ozone and soot pollution affecting more than 1.5 million people in Arizona and Northern California.

The EPA is required to ensure steps are being taken to reduce dangerous levels of these air pollutants, which harm public health and wildlife. But the agency has failed to develop air-quality plans to curb soot from fine particulate matter pollution in California’s Yolo-Solano region. The EPA has also failed to act on California’s plan to reduce soot in Plumas County and Arizona’s plans that address smog from ozone pollution in the Phoenix metro area.

Even after a decade, smog levels in the Phoenix area still exceed the 2008 science-based standard, with the worst pollution found in Scottsdale. Plumas County also had pollution above the standing in 2018, and the Yolo-Solano suffered soot pollution at more than twice the level allowed.

“The Trump EPA is sentencing thousands of Arizona and California residents to more serious breathing and heart problems,” said Robert Ukeiley, a senior attorney at the Center for Biological Diversity. “It’s disgusting that this pollution-friendly administration believes it’s fine for people to breathe filthy, unhealthy air.”

The Clean Air Act requires the EPA to develop plans to reduce particulate matter and ozone pollution when states fail to submit air-quality plans to address national air-quality standards.

Ozone and particulate matter pollution have profound effects on human health. Exposure to ozone and particulate matter can lead to decreased birth weight and premature death, respiratory and cardiovascular disease, reduced lung function and vision impairment.

“Every additional day of delay puts more Americans at risk for deadly diseases,” said Caroline Cox, research director at the Center for Environmental Health. “We're going to fight the Trump administration to ensure clean air for all American children and families.”

An EPA study found that Clean Air Act programs to reduce fine particle matter and ozone pollution prevented more than 160,000 deaths, 130,000 heart attacks and 1.7 million asthma attacks in 2010 alone. For every dollar spent, Americans have received $30 in economic benefits in return.

The Center for Biological Diversity is a national, nonprofit conservation organization with more than 1.4 million members and online activists dedicated to the protection of endangered species and wild places.

The Center for Environmental Health works with parents, communities, businesses, workers, and government to protect children and families from toxic chemicals in homes, workplaces, schools, and neighborhoods.